Schemes and formats for encoding and decoding digital speech or audio signals (hereinafter also referred to as sound signals) have been conventionally known. Representatives are the High-Efficiency Advanced Audio coding (HE-AAC) (see Non-patent Literature 1) and the Adaptive Multi-Rate Wideband (AMR-WB) format (see Non-patent Literature 2). Recently, the Unified Speech and Audio Coding (MPEG-USAC) (see Non-patent Literature 3, hereinafter referred to as USAC) has appeared which enables encoding of speech signals and audio signals with an increased efficiency.